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Nuclear Medicine in the Evaluation of Trauma. Materials for medical students. Helena Balon, MD Wm. Beaumont Hospital Royal Oak, MI, USA Charles University 3rd School of Medicine Dept Nucl Med, Prague. Radionuclide methods in traumatology. Musculoskeletal trauma Bone scan
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Nuclear Medicine in the Evaluation of Trauma Materials for medical students Helena Balon, MD Wm. Beaumont Hospital Royal Oak, MI, USA Charles University 3rd School of Medicine Dept Nucl Med, Prague
Radionuclide methods in traumatology • Musculoskeletal trauma • Bone scan • Trauma to internal organs (hematoma, laceration, fracture, perforation, leaks) • Renal scan • Myocardial scan • Hepatobiliary scan • (Liver / spleen scan) - CT preferred • (Testicular scan) - US preferred • Head trauma • CT preferred • Cerebral perfusion scan - brain death • Cisternography - CSF leak
Bone scan in trauma • Very sensitive • Detects areas of abnormal bone turnover • Shows areas that need further radiol.evaluation • Provides objective evidence of disorder when X ray negative
Bone scan • Tracers: diphosphonates (Tc-99m MDP, HDP) • Dose: 500-900MBq • Tracer localization (chemisorption onto surface of bone trabeculae) depends on: • blood flow • capillary permeability • bone metabolism (activity of osteoblasts, osteoclasts, new bone formation)
Bone scan • Patient preparation • Pre-test: none • Post-injection: good oral hydration • Frequent voiding • Perchlorate p.o. preinj. to decrease rad. dose to thyroid
Bone scan • Methods • Regular - imaging @ 2-4 hrs post injection • 3-phase (dynamic angiogram + blood pool + delay) • Planar or SPECT • Whole body ANT & POST, additional views (lat.,oblique) • Parallel hole or pinhole collimator (for small structures)
Bone Scan in Trauma • Fractures & occult fx • Child abuse (except skull fx) • Stress fractures (insufficiency fx, fatigue fx) • Avulsion injuries • Shin splints • Bone bruises (contusion) • RSD (reflex sympathetic dystrophy) • Osteochondral lesions
Diagnosis of Fractures • Plain X ray, X ray tomography - if neg >>> • Bone scan • if neg >>> stop work-up • if diagnostic >>> treat • if more information needed >>> • CT (subtle changes) or • MRI (subtle changes, soft tissue trauma, bone bruise, precise dx of limited area)
Fractures on Bone scan • Acute fx • Positive on all 3 phases • Positive immediately after trauma in most pts • 90% sensitivity if imaged in < 48 hrs • If scan neg. in pts > 75y >>> repeat scan in 3-7 d • Bone scan remains positive for 6-24 mo (healing fx)
Acute compression fractures 80 y/o F w osteopeniafell 6 wks prior
Multiple fx’s 59 F w breast caMVA 10 d ago
Bone Bruise • Direct trauma with disruption of trabecular bone but not cortical bone • X ray - negative • Bone scan - 3-phase positivity • MRI - bone marrow involvement (hemorrhage)
Shin / thigh splints • Continuous spectrum from shin splint to stress fx • Stress related periostitis along muscle insertion sites (soleus, tibialis posterior, adductor longus/brevis, gluteus max) • X ray - negative • Bone scan • Flow, blood pool - normal • Delay- vertical, linear uptake along posteromedial tibial cortex (mid- or distal 1/3) medial or lateral femoral cortex (proximal 1/3)
Stress Fractures • Fatigue fractures Abnormal stress on normal bone (jogging, gymnastics, skating, military) • Insufficiency fractures Normal stress on abnormal bone (osteoporosis, osteomalacia, RA, HPT, steroids, radiation Rx)
Stress fractures • Pathophysiology - repetitive microtrauma (athletes) • Symptoms - pain, swelling • Common locations: • Tibia - proximal or distal 1/3 • Fibula - distal 1/3 • Metatarsals (2nd, 3rd) • Tarsal bones (calcaneus, navicular) • Femoral neck • Inferior pubic ramus • Lower lumbar spine (spondylolysis)
Stress fractures • X ray may be initially negative (2-4 wks) • Bone scan, MRI – positive earlier • Bone scan 3-phase positivity • Flow + for ~ 1 mo • Blood pool + for ~ 2 mo • Delay + for ~ 9-12 mo • Rx - restrict sports for 4-6 wks
Plantar fasciitis • Heel pain • Post-traumatic inflammation of plantar ligament due to • athletic overuse • prolonged standing • walking on hard surface • Bone scan Focal blood pool + delayed uptake in inferior posterior calcaneus
Impingement syndromes • Posterior impingement sy (os trigonum sy) • Excessive repeat plantar flexion (compression between posterior calcaneus & posterior tibia) • Ballet dancers, gymnasts • Anterior impingement sy • Excessive repeat dorsal flexion >>> hypertrophic spur on dorsum (talus & anterior tibia) • Ballet dancers, gymnasts, high jumping
Posterior impingement syndrome(os trigonum stress fx) 2078102
Femoral neck stress fracture • Thigh or groin pain in athletes • Must distinguish femoral neck stress fx from pubic ramus stress fx • Must treat / immobilize early to prevent complete fx, AVN
Femoral neck Fx 76F w L groin pain X ray neg
Intertrochanteric fracture 93 F, fall 6 days ago, Rt hip pain
Avascular necrosis (AVN) • Etiology • trauma (fx) • steroids, alcohol abuse • pancreatitis, fat embolism • vasculitis, SS disease • idiopathic • Pathophysiology: bone ischemia • Diagnosis • MRI most sensitive • bone scan useful
AVN • Common locations • Femoral head (Legg-Perthes in children) • Carpal (scaphoid, lunate), tarsal (talus) • Long bones, ribs in SS • Bone scan • Initially “cold” • Revascularization starts in 1-3 wks, from periphery, diffusely “hot”, lasts for months
IT Fx + AVN 50 M w fall a few weeks ago
IT fx + AVN MRI
Sacrococcygeal Fx ANT POST
Sacral insufficiency fx ANT POST 79 F fell 1 mo ago(“Honda” sign)
Pelvic fractures 4 days post fall 1 month later
Spondylolysis • Stress fx of posterior vertebral elements (pars interarticularis) due to repetitive trauma • Teenagers, young adults • Hyperextension sports (gymnastics, diving, weight lifting, soccer,hockey) • Genetic predisposition? • L5 > L4 > L3 • Frequently bilateral >>> spondylolisthesis
Spondylolysis • X ray Normal or sclerosis, later lucency 2º fx • Bone scanincreased uptake in pars interarticularis SPECT better than planar • Rx – discontinue activity